Heart failure
### Heart Failure
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#### 1. Basic Disease Identification
- Name of the Disease: Heart Failure (HF)
- Synonyms: Congestive Heart Failure (CHF), Cardiac Failure
- ICD-10/ICD-11 Code:
- ICD-10: I50 (Heart failure)
- ICD-11: 4A00 (Heart failure)
- Other Classifications:
- Left-sided heart failure (HFrEF, HFpEF)
- Right-sided heart failure (isolated right-sided or secondary to left-sided failure)
- Acute vs Chronic: Heart failure can be categorized into acute or chronic, with different pathophysiological processes and treatment approaches.
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#### 2. Overview
- Brief Description:
Heart failure is a clinical syndrome where the heart is unable to pump blood effectively to meet the body's demands, leading to symptoms of fluid retention (e.g., pulmonary edema, peripheral edema), fatigue, and shortness of breath.
- Historical Background:
The concept of heart failure dates back to ancient medicine, with significant advances in the 20th century. Key developments included the recognition of distinct left- and right-sided heart failure, improved diagnostic modalities like echocardiography, and the development of pharmacologic agents such as ACE inhibitors and beta-blockers to improve survival.
- Epidemiology:
- Global Prevalence: Heart failure affects approximately 1-2% of the adult population, with the prevalence increasing with age.
- Age, Gender, Ethnicity Distribution: More common in older adults, particularly those over 65. Males tend to develop heart failure at a younger age, while females tend to experience heart failure with preserved ejection fraction (HFpEF) at older ages.
- Risk Factors: Hypertension, coronary artery disease, diabetes, obesity, smoking, and a family history of heart disease.
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#### 3. Etiology (Causes)
- Primary Causes:
- Coronary Artery Disease (CAD): The most common cause of heart failure, resulting from myocardial infarction or chronic ischemia.
- Hypertension: Longstanding high blood pressure leads to left ventricular hypertrophy and eventually to heart failure.
- Valvular Heart Disease: Aortic or mitral valve diseases can result in volume or pressure overload of the heart, leading to heart failure.
- Cardiomyopathies: These include dilated, hypertrophic, and restrictive cardiomyopathies.
- Arrhythmias: Tachyarrhythmias (e.g., atrial fibrillation) or bradyarrhythmias (e.g., complete heart block) may contribute to heart failure.
- Secondary Causes:
- Endocrine disorders: Diabetes, hyperthyroidism, and hypothyroidism.
- Chronic kidney disease: The cardiorenal syndrome links kidney dysfunction with heart failure.
- Toxins: Alcohol abuse, chemotherapy (e.g., doxorubicin), and illicit drug use (e.g., cocaine).
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#### 4. Pathophysiology
- Mechanism of Disease:
Heart failure can result from either impaired systolic function (inability of the heart to contract properly) or impaired diastolic function (inability of the heart to relax and fill properly).
- Systolic Dysfunction (HFrEF): Reduced ejection fraction (<40%). Due to damaged myocardial tissue (e.g., from ischemia, infarction, or cardiomyopathy), the heart loses its ability to contract effectively.
- Diastolic Dysfunction (HFpEF): Normal or near-normal ejection fraction, but the heart's ability to relax and fill properly is impaired. This often occurs due to myocardial stiffness, commonly seen in hypertension and aging.
- Involved Organs & Systems:
- The heart is directly affected, with either impaired contraction or relaxation.
- The kidneys are affected due to the activation of the renin-angiotensin-aldosterone system (RAAS), leading to sodium retention and fluid overload.
- Lungs often show signs of congestion due to left-sided heart failure (pulmonary edema).
- Peripheral tissues may exhibit signs of fluid retention and reduced perfusion.
- Pathogenesis Timeline:
The progression of heart failure can be gradual, especially with conditions like hypertension or CAD, but it can also occur acutely after an event like a myocardial infarction.
- Biochemical Pathways:
- Neurohormonal Activation: Activation of the sympathetic nervous system (SNS), RAAS, and vasopressin results in fluid retention, vasoconstriction, and increased heart rate.
- Inflammation: Chronic heart failure often involves inflammatory pathways that contribute to myocardial injury and remodeling.
- Associated Anatomical and Physiological Changes:
- Left ventricular hypertrophy due to chronic pressure overload.
- Dilatation of the heart chambers, particularly the left ventricle in systolic dysfunction.
- Pulmonary congestion leading to symptoms like orthopnea and paroxysmal nocturnal dyspnea.
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#### 5. Clinical Features
- Signs and Symptoms:
- Primary Symptoms: Dyspnea, fatigue, orthopnea, paroxysmal nocturnal dyspnea, reduced exercise tolerance, and edema (peripheral and pulmonary).
- Secondary Symptoms: Hepatomegaly, jugular venous distension, crackles on lung auscultation, ascites, and weight gain from fluid retention.
- Disease-Specific:
- Left-sided heart failure: Pulmonary symptoms such as shortness of breath, cough, and frothy sputum.
- Right-sided heart failure: Symptoms related to systemic venous congestion, including peripheral edema, ascites, and jugular venous distension.
- Complications:
- Cardiogenic Shock: Acute, severe heart failure leading to hypotension and multi-organ failure.
- Arrhythmias: Atrial fibrillation, ventricular arrhythmias, and sudden cardiac death.
- Thromboembolism: Especially in the setting of atrial fibrillation.
- Disease Variants/Subtypes:
- Acute vs Chronic: Acute heart failure often results from a sudden event (e.g., myocardial infarction), while chronic heart failure develops over time from conditions like hypertension and CAD.
- HFrEF vs HFpEF: The two main phenotypes based on the left ventricular ejection fraction.
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#### 6. Diagnostic Criteria
- Diagnostic Guidelines:
- Diagnosis is made based on clinical symptoms, physical examination, and imaging studies.
- ESC (European Society of Cardiology) guidelines and AHA/ACC guidelines outline specific diagnostic criteria, such as symptoms of congestion (e.g., orthopnea) and evidence of left ventricular dysfunction on echocardiography.
- Differential Diagnosis:
- Pulmonary diseases (e.g., chronic obstructive pulmonary disease), renal failure, and anemia can mimic symptoms of heart failure.
- Laboratory Investigations:
- B-type natriuretic peptide (BNP) and N-terminal pro B-type natriuretic peptide (NT-proBNP) levels, which are elevated in heart failure.
- Serum electrolytes, renal function tests, and liver function tests.
- Thyroid function tests to rule out hypothyroidism or hyperthyroidism.
- Imaging Studies:
- Echocardiography: The key imaging modality for assessing left ventricular ejection fraction (LVEF), diastolic dysfunction, and valvular abnormalities.
- Chest X-ray: To evaluate pulmonary congestion (e.g., Kerley B lines, pleural effusion).
- Cardiac MRI: Useful for evaluating myocardial tissue, especially in cases of myocarditis or cardiomyopathy.
- Electrocardiogram (ECG): To assess for arrhythmias (e.g., atrial fibrillation) and signs of ischemia or previous infarction.
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#### 7. Management and Treatment
- Acute Management:
- Diuretics (e.g., furosemide) for fluid removal.
- Vasodilators (e.g., nitroglycerin) to reduce preload and afterload.
- Inotropes (e.g., dobutamine, milrinone) in cases of cardiogenic shock.
- Oxygen therapy to manage hypoxemia.
- Medical Treatment:
- ACE inhibitors/ARBs (e.g., enalapril, losartan) to block RAAS and reduce heart failure symptoms.
- Beta-blockers (e.g., metoprolol, carvedilol) to improve left ventricular function and reduce mortality.
- Aldosterone antagonists (e.g., spironolactone) to reduce fluid retention and improve survival.
- Angiotensin receptor-neprilysin inhibitors (ARNIs) (e.g., sacubitril/valsartan) for improved outcomes in HFrEF.
- SGLT2 inhibitors (
e.g., empagliflozin) for managing heart failure with preserved ejection fraction (HFpEF) and HFrEF.
- Device Therapy:
- Implantable Cardioverter Defibrillator (ICD) for patients at high risk for sudden cardiac death.
- Cardiac Resynchronization Therapy (CRT) for patients with heart failure and a prolonged QRS complex.
- Surgical Treatment:
- Heart transplantation for end-stage heart failure.
- Ventricular assist devices (VADs) as a bridge to heart transplantation or long-term support.
- Lifestyle Management:
- Dietary changes: Low-sodium diet, fluid restriction.
- Exercise: Tailored to patient tolerance.
- Smoking cessation and alcohol restriction.
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#### 8. Prevention and Screening
- Primary Prevention:
- Lifestyle changes to reduce risk factors like hypertension, diabetes, and obesity.
- Regular monitoring and treatment of chronic conditions that predispose to heart failure, such as hypertension and CAD.
- Secondary Prevention:
- Regular follow-up for patients with a history of myocardial infarction, hypertension, or cardiomyopathy.
- Monitoring of symptoms and biomarkers (e.g., BNP) in at-risk individuals.
- Tertiary Prevention:
- Post-discharge care for patients hospitalized for heart failure, including medication adherence, lifestyle management, and symptom monitoring.
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#### 9. Patient Education and Self-Care
- Essential Patient Information:
- Understanding the importance of adhering to medications, especially ACE inhibitors, beta-blockers, and diuretics.
- Recognizing symptoms of worsening heart failure (e.g., increased dyspnea, edema).
- Self-Monitoring Guidelines:
- Daily weight measurement to monitor for fluid retention.
- Blood pressure and pulse rate monitoring.
- Keeping track of physical activity and exercise tolerance.
- Lifestyle Modifications:
- Diet: Low-sodium, fluid-restricted diet.
- Regular moderate exercise as tolerated.
- Avoiding alcohol, smoking, and drugs.
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#### 10. Recent Research and Advancements
- Latest Findings:
- Advancements in genetic testing and personalized medicine in heart failure management.
- Ongoing studies into the role of SGLT2 inhibitors in heart failure management.
- Emerging Therapies:
- Investigational drugs targeting novel pathways, such as fibrosis, inflammation, and mitochondrial dysfunction.
- Use of gene therapy for improving myocardial function.
- Innovative Technologies:
- Wearable devices for continuous monitoring of heart failure symptoms and parameters.
- AI and machine learning in predicting heart failure progression.
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#### 11. Prognosis and Complications
- Expected Disease Course:
The course of heart failure is variable; with appropriate management, many patients can maintain good quality of life. However, heart failure is a progressive condition, and end-stage heart failure requires advanced therapies like heart transplantation.
- Common Complications:
- Arrhythmias (e.g., atrial fibrillation, ventricular tachycardia).
- Thromboembolism, especially in patients with atrial fibrillation.
- Renal dysfunction, often due to poor perfusion.
- Long-Term Outlook:
Mortality rates remain high for patients with advanced heart failure, though early intervention and medical management improve prognosis.
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#### 12. References and Further Reading
- Evidence-Based Guidelines: ESC, AHA/ACC heart failure management guidelines.
- Clinical Trials: Ongoing trials evaluating the role of new pharmacologic agents like SGLT2 inhibitors and ARNI.
- Review Articles and Textbooks: "Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine."